Ethernet has low cost of the apparatus and many choices of communication speed, so that the management operation is easy. Therefore, Ethernet has been widely spread as a Local Area Network (LAN) such as a corporate LAN or a wide-area LAN service such as a Layer2-Virtual Private Network (L2-VPN). The wide-area LAN service is a network in which a protocol of a layer 3 , a higher protocol of a layer 2 , is not selected, that is, an Internet Protocol (IP) topology-free network where a user may freely design and operate an IP network.
For example, the user may use a dynamic routing protocol such as Routing Information Protocol/Open Shortest Path First (RIP/OSPF) to perform dynamic path control. Furthermore, for example, the user perform simple path setting by using a static route. Patent Document 1 proposes a method for determining whether or not occurrence of flooding with respect to an address meets a prescribed condition in a frame switching apparatus that switches the frame, receiving a prescribed report transmitted from another switch that stores the same address entry as the address that meets the prescribed condition, and registering the address entry by which the address that meets the prescribed condition is associated with a port that receives the report.
Patent Document 2 proposes that if a prescribed LAN terminal does not register a Media Access Control (MAC) address of another LAN terminal, an address resolution request is transmitted to a router, and the router transmits the address resolution request to the other LAN terminal and updates an address resolution table based on address resolution information sent back from the other LAN terminal to transmit the address resolution information to the prescribed LAN terminal.
Moreover, Patent Document 3 proposes a method for providing an Address Resolution Protocol server module in a switching hub, giving all the broad cast frames received by an interface module to the above-described ARP server module, and replying from a reception port after an ARP reply frame is built if there is an entry corresponding to the network address.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2010-045657
[Patent Document 2] Japanese Laid-open Patent Publication No. 2002-111700
[Patent Document 3] Japanese Laid-open Patent Publication No. 09-064900